Initializing components of an integrated circuit

ABSTRACT

Methods, systems, and computer program products for initializing one or more components of a system, the system comprising an integrated circuit that comprises at least one processor, are disclosed. A method includes initializing at least one component of the system, determining a temperature of the integrated circuit using a temperature sensing device embedded on the integrated circuit, comparing the determined temperature to a predetermined suitable temperature operating range of at least one additional component to yield a comparison result, and initializing the at least one additional component based on the comparison result. The at least one additional component may be initialized on the condition that the determined temperature of the integrated circuit is within the predetermined suitable temperature operating range of the at least one additional component.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. application Ser.No. 13/236,340 filed on Sep. 19, 2011 which is a continuation-in-part ofU.S. application Ser. No. 12/851,602 filed on Aug. 6, 2010.

BACKGROUND

Bringing up a system, such as an integrated circuit, in a hostileenvironment presents several challenges because, among other things,components of an IC chip typically operate at different conditions. Forexample, the PLL (phase-locked loop) and eDRAM components of a chip mayrequire a warmer temperature range than other chip components in orderto function adequately.

SUMMARY

In one embodiment of the invention, a method for initializing one ormore components of a system, the system comprising an integrated circuitthat comprises at least one processor, is disclosed. The methodcomprises: initializing at least one component of the system;determining a temperature of the integrated circuit using a temperaturesensing device embedded on the integrated circuit; comparing thedetermined temperature to a predetermined suitable temperature operatingrange of at least one additional component to yield a comparison result;and initializing the at least one additional component based on thecomparison result.

In another embodiment of the invention, a system for initializing one ormore components of an integrated circuit is disclosed. The systemcomprises: a temperature sensing device embedded on the integratedcircuit that determines a temperature of the integrated circuit; and atleast one processor. The at least one processor initializes at least onecomponent of the integrated circuit; compares the determined temperatureto a predetermined suitable temperature operating range of at least oneadditional component to yield a comparison result; and initializes theat least one additional component based on the comparison result.

In another embodiment of the invention, a computer-readable mediumstoring computer program code for causing a computer to perform aprocess, the computer comprising an integrated circuit, is disclosed.The process comprises instructions for: initializing at least onecomponent of the integrated circuit; determining a temperature of theintegrated circuit using a temperature sensing device embedded on theintegrated circuit; comparing the determined temperature to apredetermined suitable temperature operating range of at least oneadditional component to yield a comparison result; and initializing theat least one additional component based on the comparison result.

These and other embodiments of the invention are described in detailwith reference to the following drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a schematic block diagram of a system in accordance withone or more embodiments of the invention.

FIG. 2 depicts a flow chart illustrating a method in accordance with anembodiment of the invention.

FIG. 3 depicts a flow chart illustrating a method in accordance with anembodiment of the invention.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. A computer readable storage medium may be a transitory or anon-transitory medium, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of non-transitory computerreadable storage media include the following: a portable computerdiskette, a hard disk, a random access memory (RAM), a read-only memory(ROM), an erasable programmable read-only memory (EPROM or Flashmemory), a portable compact disc read-only memory (CD-ROM), an opticalstorage device, a magnetic storage device, or any suitable combinationof the foregoing. In the context of this document, a computer readablestorage medium may be any tangible medium that can contain, or store aprogram for use by or in connection with an instruction executionsystem, apparatus, or device. Program code embodied on a computerreadable medium may be transmitted using any appropriate medium,including but not limited to wireless, wireline, optical fiber cable,RF, etc., or any suitable combination of the foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, may be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks. The computer program instructions may also beloaded onto a computer, other programmable data processing apparatus, orother devices to cause a series of operational steps to be performed onthe computer, other programmable apparatus or other devices to produce acomputer implemented process such that the instructions which execute onthe computer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

Referring now to FIG. 1, a schematic block diagram of a system 100 inaccordance with one or more embodiments of the invention is shown. Thesystem may be, for example, a System-On-a-Chip (SOC) in which thevarious components are integrated on a single integrated circuit. In thealternative, the system may be an Application-specific integratedcircuit (ASIC) that is customized for a particular use, an applicationspecific standard product, or an industry standard integrated circuit.Alternately, the system 100 may be a combination of any number ofintegrated circuits such that the various components shown aredistributed across the integrated circuits. One of ordinary skill in theart will appreciate that the system 100 may take on various formsdepending on the particular characteristics of the computing environmentin which it will be employed.

The system 100 includes a central processing unit (CPU) 101 which mayinclude one or more microprocessors, direct memory access 102, embeddeddynamic random access memory (DRAM) 105, a memory controller 106, andvarious other components 103. One of ordinary skill in the art willappreciate that the other components 103 may include additional memoryblocks in the form of ROM, RAM, EEPROM, and Flash memory, externalinterfaces including industry standards such as USB, Firewire, Ethernet,USART, or SPI, analog interfaces, voltage regulators, power managementcircuits, or any other suitable or desired component. The system 100additionally includes a processor local bus 104 through which the CPU101 may communicate with, read data from, or write data to at least theembedded DRAM 105, the memory controller 106, the direct memory access102, and the other components 103. The system 100 further includes aclock and reset control module 107. The clock and reset control module107 may include timing sources such as oscillators and phase-lockedloops (PLLs). The clock and reset control module 107 may also includeperipherals such as counter-times, real-time timers and power-on resetgenerators.

In addition, the clock and reset control module 107 may comprise atemperature or thermal sensing device. The temperature sensing devicemay alternatively be provided outside of the clock and reset controlmodule 107. In either case, in accordance with one or more embodimentsof the invention, the temperature sensing device is embedded on thesystem 100. As noted previously, in one or more embodiments of theinvention, the system 100 may be a SOC or an ASIC. In these embodimentsthe temperature sensing device may be embedded on the integratedcircuit.

Booting up an integrated circuit (IC) chip or system in a hostileenvironment such as an arctic environment in which average temperaturesare significantly lower than typical temperatures at which the IC chipor system is generally designed to operate presents several challenges.Certain chip components may require different temperature ranges thanthose required by other components in order to function properly. Forexample, assuming that an IC chip is being booted up in a particularlycold environment, the phase-locked loop and eDRAM components of the ICchip may require warmer temperature ranges than what other componentsrequire in order to operate adequately. Certain components of the chipmay be capable of being initialized or enabled during initial stages ofthe boot-up process at lower ambient temperatures, while othercomponents (such as the PLL and the eDRAM components) may require theambient temperature around the chip to rise to an appropriate level by,for example, the heat generated during the boot-up process before thesecomponents may be enabled or initialized. Similarly, in an environmentin which temperatures exceed the typical temperatures at whichcomponents of an IC chip are designed to operate at, certain componentsmay require the ambient temperature around the chip to cool to a certainlevel before these components may be enabled or initialized and expectedto perform properly.

Conventional systems employ a thermal sensing device disposed externallyto the IC chip to indicate when the temperature conditions areappropriate for the chip to be powered up. The use of an externaltemperature sensing device is costly as it must be separatelymanufactured and installed in the system. In addition, temperaturemeasurements obtained from an external thermal sensing device are ofteninaccurate due to the inability of the external thermal sensing deviceto accurately measure the junction temperature of the chip. As such, theinherent inaccuracy of measurement of external thermal sensing devicesresults in longer chip boot-up times caused by the necessity tocompensate for the measurement error.

Embedding the temperature sensing device within or on an IC chip (i.e.forming the temperature sensing device from the same wafer ofsemiconductor material as other components of the IC chip) providesdistinct advantages over conventional systems that employ an externaltemperature sensing device. Embedded temperature sensing devices inaccordance with one or more embodiments of the invention results insignificant cost reductions as compared to external devices. An embeddedtemperature sensing device according to one or more embodiments of theinvention is relatively small and generally will not require an increasein the die size of the IC chip. Further, embedded temperature sensingdevices are capable of more accurately measuring the junctiontemperature of the IC chip, and thus do not suffer from the measurementinaccuracies of external thermal sensing devices and the resultantlonger chip boot-up times.

In accordance with one or more embodiments of the invention, one or morereset sequences may be employed in conjunction with the system 100 ofFIG. 1 that comprises an embedded temperature sensing device in order toperform a booting-up or bringing-up process of the system in aneffective and efficient manner. An example of such a reset sequence inaccordance with an embodiment of the invention is depicted in the flowchart of FIG. 2.

According to an embodiment of the invention, in the method depicted inFIG. 2, a start-up of the IC chip is initiated (S200). Prior to or atthe start-up of the chip, all components of the chip may be in a resetstate. The start-up of the chip may include running the system BIOS toenable the processor. Although this method is described with referenceto a single integrated circuit chip, one of ordinary skill in the artwill appreciate that this method may be applicable to any suitablesystem. In step S201, a first set of components may be enabled to startthe booting-up process. The first set of components may include onlythose components that are known to function at startup conditions. Aspart of either step S200 and/or S201, the CPU (which may be one or moremicroprocessors) is enabled and a clock signal associated with the CPUmay be synchronized with a reference clock signal that is slower thanthe phase-locked loop (PLL) clock signal. Further, at this stage, theCPU cache memory may be disabled. In addition, the first set ofcomponents that are enabled in step S201 may include read-only memory(ROM) modules and various other components that are capable of operatingat the current chip temperature and that do not necessarily require aspecific temperature range to be present in order to function properly.

In step S202, periodic temperature measurements are recorded by thetemperature sensing device that is embedded on the chip. Then, in stepsS203 and S204, the periodic temperature measurements are compared to anormal PLL temperature operating range and a normal DRAM temperatureoperating range, respectively, to yield comparison results. In one ormore embodiments of the invention, the CPU may be provided with a set ofsoftware instructions that enables the CPU to perform the requiredcomparisons of steps S203 and S204. If it is determined in step S203that the measured temperature falls within the PLL temperature operatingrange, then in step S205, the PLL is enabled and the CPU clock signal issynchronized with the faster PLL clock signal. The PLL may be, forexample, a clock generator PLL that multiplies a lower frequencyreference clock up to the operating frequency of the CPU. Similarly, ifit is determined in step S204 that the measured temperature is withinthe eDRAM temperature operating range, in step S206, the eDRAM is markedas available for use by the CPU. Thereafter, in step S207, thebooting-up process of the chip is continued.

The enabling of the first set of components in step S201 may be thoughtof as occurring independently of the temperature measurements. That is,the first set of components includes those chip components that arecapable of operating at the current chip temperature and do not requirea change in the temperature to a specific temperature range in order tooperate properly. Further, although the reset sequence or methoddepicted in FIG. 2 only explicitly discusses a comparison of themeasured temperature with the PLL temperature operating range and theeDRAM temperature operating range, any number of other components may beenabled based on a comparison result obtained by comparing the periodictemperature measurements to a specified temperature operating range forthat component. For example, various forms of memory such as cache SRAM,non-cache SRAM, double data rate (DDR) memory such as DDR SRAM, DDRSDRAM, as well as any number of other IC chip components may be enabledbased on a comparison of the periodic temperature measurements obtainedfrom the embedded temperature sensing device to a specific temperatureoperating range that corresponds to the component.

FIG. 3 provides a flow chart that illustrates an embodiment of theinvention. The embodiment shown in FIG. 3 should not be viewed aslimiting and one of ordinary skill in the art will appreciate thatnumerous variations of the embodiment are within the scope of theinvention.

The implementation 300 depicted in FIG. 3 begins with a power-on resetthat initiates a reset stretch 301 that applies a reset 305 to allcomponents excluding the PLL and the eDRAM. To reiterate, this specificimplementation is not limiting and other implementations that do notreset other IC chip components are clearly within the scope of theinvention.

An embedded temperature sensor 302 such as that previously described isprovided. The temperature sensor 302 obtains periodic temperaturemeasurements of the chip temperature. At decision block 304, acomparator (which may be the CPU itself) compares the temperaturemeasurements obtained by the temperature sensor 302 with the suitabletemperature operating range for the PLL 303. If it is determined thatthe measured temperature does not fall within the suitable temperatureoperating range for the PLL, then the comparator continues to performcomparisons of the periodic temperature measurements to the suitabletemperature operating range of the PLL.

If it is determined that the measured temperature does fall within thesuitable temperature operating range for the PLL, then an input 306A tothe S-R latch 306 is toggled. As part of the initial booting-up of thechip, an additional input 306B is also provided to the S-R latch 306. Assuch, until the input 306A is toggled when the measured temperature iswithin the suitable temperature operating range for the PLL, the S-Rlatch provides a control signal to the multiplexer 307 that results in amapping of the input representative of the reference clock signal to theCPU clock signal. In other words, as long as the measured temperature isnot within the suitable temperature operating range for the PLL, the CPUclock signal is synchronized to the reference clock signal.

However, when the input 306A is toggled based on the measuredtemperature being within the suitable temperature operating range forthe PLL, the S-R latch 306 provides a control signal to the multiplexer307 that results in a mapping of the faster PLL clock to the CPU clock.That is, the CPU clock signal is synchronized with the faster PLL clock.In one or more embodiments of the invention, the multiplexer 307 may bea glitchless multiplexer.

FIG. 3 depicts a specific implementation according to one or moreembodiments of the invention. However, one of ordinary skill in the artwill appreciate that numerous other implementations that involve otherreset sequences and additional components are within the scope of theinvention.

The flowchart and block diagrams in the Figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the invention. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose.

What is claimed is:
 1. A system for initializing one or more componentsof an integrated circuit, the system comprising: a temperature sensingdevice embedded on the integrated circuit that determines a temperatureof the integrated circuit; a phase-locked loop; and at least oneprocessor that: initializes at least one component of the integratedcircuit; determines a temperature of the integrated circuit using thetemperature sensing device; compares the determined temperature to apredetermined suitable temperature operating range of at least oneadditional component to yield a comparison result; and initializes, independence on the comparison result, the at least one additionalcomponent, wherein prior to the initializing the at least one additionalcomponent: the at least one processor is enabled, and a clock signalassociated with the at least one processor is synchronized with a signalof a reference clock, wherein the signal of the reference clock isslower than a signal of a clock associated with the phase-locked loop,and wherein the initializing the at least one additional componentfurther comprises: synchronizing the clock signal of the at least oneprocessor with the phase-locked loop clock signal on the condition thatthe determined temperature is within a predetermined suitabletemperature operating range for the phase-locked loop.
 2. The system ofclaim 1, wherein the system further comprises a multiplexer, and whereina mapping signal is provided to the multiplexer to synchronize the clocksignal associated with the at least one processor with the referenceclock signal.
 3. The system of claim 1, wherein prior to the at leastone processor initializing the at least one component, all components ofthe integrated circuit are in a reset state.
 4. The system of claim 1,wherein the clock signal of the at least one processor is continued tobe synchronized with the reference clock signal as long as thedetermined temperature is outside the predetermined suitable temperatureoperating range of the phase-locked loop.
 5. The system of claim 4,wherein the clock signal of the at least one processor is set to a clocksignal of the phase-locked loop.
 6. The system of claim 1, wherein thedetermining a temperature of the integrated circuit comprises obtainingperiodic measurements of the temperature of the integrated circuit atspecified intervals from the temperature sensing device.
 7. Acomputer-readable medium storing computer program code for causing acomputer to perform a process, the computer comprising an integratedcircuit, the process comprising instructions for: initializing at leastone component of the integrated circuit; determining a temperature ofthe integrated circuit using a temperature sensing device embedded onthe integrated circuit; comparing the determined temperature to apredetermined suitable temperature operating range of at least oneadditional component to yield a comparison result; and initializing theat least one additional component based on the comparison result,wherein prior to the initializing the at least one additional component:an at least one processor is enabled, and a clock signal associated withthe at least one processor is synchronized with a signal of a referenceclock, wherein the signal of the reference clock is slower than a signalof a clock associated with a phase locked loop, and wherein theinitializing the at least one additional component further comprises:synchronizing the clock signal of the at least one processor with thephase-locked loop clock signal on the condition that the determinedtemperature is within a predetermined suitable temperature operatingrange for the phase-locked loop.
 8. The computer-readable medium ofclaim 7, wherein prior to the at least one processor initializing the atleast one component, all components of the integrated circuit are in areset state.
 9. The computer-readable medium of claim 7, wherein theclock signal of the at least one processor is continued to besynchronized with the reference clock signal as long as the determinedtemperature is outside the predetermined suitable temperature operatingrange of the phase-locked loop.
 10. The computer-readable medium ofclaim 8, wherein the clock signal of the at least one processor is setto a clock signal of the phase-locked loop.
 11. The computer-readablemedium of claim 7, wherein the determining a temperature of theintegrated circuit comprises obtaining periodic measurements of thetemperature of the integrated circuit at specified intervals from thetemperature sensing device.